Using Std Rads with low temp heat source

Mazotasan

Is it possible to use standard rads (normally used with Boiler say) in conjunction with a low temp heat source such as a heat pump. For example oversizing the rads...Is it really just not efficient/cost effective or can it be done based upon heat loss calculations.

We have carried out a pre BER resulting in a B1 excluding the reneweables element. I kinda had resorted to the solar panels to fulfill the part L and now having second thoughts, problem is we have 1st fix plumbing in for rads and now considering something like this http://www.nibe.eu/Domestic-heatingcooling/Exhaust-air-heat-pumps/Product-range/FIGHTER-640P/ Any thoughts/experiences appreciated...

holdfast

In short no HP and rads do not work, if use the design tables for rads they allow for such low temps. You could go with HP and oil with a system interlink. this would bring the water up to 70 deg for the rads. Have you looked at wood chip etc boilers to satisify part L.

RavenII

Rads and heatpump is no problem, they are simply left running at a lower temperature for a longer period compared to their on/off bursts on oil. A good heatpump will provide weater-linked control for both rads and floor heating to minimise running costs. In Scandinavia there are many homes with radiators heated by heatpumps

sydthebeat

its possible to do.... but low heat source are much more suited to passive radiant emitters such as underfloor heating.

radiators are specifically design to give off high short bursts of heat, which you do not get with heat pumps.....

personally, i wouldnt take the risk.... heat pump systems are expensive enough without risking an emitter that may not work....

tred

Did I read somewhere, people were over sizing the rads to handle the constant lower temp??? for say the HP..

bbam

Mazotasan wrote: »

I kinda had resorted to the solar panels to fulfill the part L and now having second thoughts,

What is putting you off the solar... We went with 5.5sq m of flat panel and are very happy.. We never have to put on the oil for hot water and in 18 months have only put on the immersion for a total of about 2-3 hours (she likes a scalding hot shower).

imitation

I wouldnt try it with normal rads. Its a constant complaint from one of my friends that his 1st floor alurads dont output enough heat. I'm no expert, but I believe that they are supposed to be more suited to a low temp system than normal rads too.

RavenII

Its a complete old wives tale that you MUST have floor heating with a heat pump. In perhaps 90 % of retro fits you don't have to change the radiators either, but the heating system is run differently; its left running all the time linked to the weather (this doesn't mean it's consuming all the time ; the compressor kicks in and out as necessary). If an area of a house with rads is colder, in a mixed system with UFH, it will be because they forgot to seperately control the two; the radiators wiil need to be hotter, say 55° with an out side temp of -3° ...the floor heating about 40°C on the same night.

Turning on / off rads with oil etc in gulches of heat on a timer you'll probably run the rads at 70° or so.

By the way, they outlawed rads running at higher than 55°C in Sweden in 1975! If not on district heating most family homes use heatpumps there.